Fig. 3. ERK phosphorylation in MDA-MB-231 cells treated with uPA- or uPAR-specific antibody. Cells were treated for 24 hours with uPA-specific antibody (panel A), uPAR-specific antibody (panel B) or nonimmune IgG from mouse or rabbit (panel C). Lanes labeled ‘-’ were treated with vehicle. Cell extracts were subjected to SDS-PAGE and electrotransfered to nitrocellulose membranes, which were probed to detect phosphorylated ERK, stripped and then re-probed to detect total ERK. Duplicate determinations from separate cultures are shown in panels A and B.